Card-type terminals have been known, examples of which include a card-type terminal that uses WiMAX (Worldwide Interoperability for Microwave Access) technologies, a card-shaped terminal that is used as an antenna when implementing a USB (Universal Serial Bus) wirelessly through the use of UWB (UltraWideBand) technologies, and other card-type terminals that use a wireless LAN (Local Area Network) or wireless technologies for data communication. One of the recent trends has been to enhance functionality for implementing such terminals as a single card-type terminal. A wideband antenna is thus absolutely essential for this kind of terminal.
FIG. 35 describes the configuration of an antenna of the related art for use in such a card-type terminal. In the diagram, a printed circuit board 100 has a first area (an area on the rear-end side of the card-type terminal) a1, which includes a circuit component mounting area of a peripheral circuit section, and a remaining second area (an area on the top-end side of the card-type terminal) a2 at different positions in one direction (Y direction in the diagram) so as to extend along another direction (X direction in the diagram) between the two mutually-orthogonal directions defined by the rectangular body (X and Y directions in the diagram). The first area a1 is provided with a microstrip line 111 and an underlying, ground conductor 112. The ground conductor 112 constitutes a ground-side conductor of the peripheral circuit section which is arranged in the circuit component mounting area, and a ground-side conductor of the microstrip line 111. Meanwhile, the second area a2 is provided with an antenna section which is connected with the microstrip line 111. The antenna section includes a circular plate element 110 which constitutes the antenna's radiating element. The circular plate element 110 is electrically fed by the peripheral circuit section through the microstrip line 111.
Patent Document 1 discloses a method of mounting an antenna on a wireless communication adaptor device. In the method, when a chip element and an antenna feeding point on a ground conductor plate are connected with a strip element, the strip element is laid so that an electrical length from the antenna feeding point to the top of the chip element is approximately one half the wavelength of the use frequency.
Patent Document 1: JP-A-2005-020369